/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.sinosoft.monitor.org.objectweb.asm.commons;

import java.util.Collections;
import java.util.Comparator;

import com.sinosoft.monitor.org.objectweb.asm.MethodVisitor;
import com.sinosoft.monitor.org.objectweb.asm.Opcodes;
import com.sinosoft.monitor.org.objectweb.asm.tree.MethodNode;
import com.sinosoft.monitor.org.objectweb.asm.tree.TryCatchBlockNode;

/**
 * A {@link MethodVisitor} adapter to sort the exception handlers. The handlers
 * are sorted in a method innermost-to-outermost. This allows the programmer to
 * add handlers without worrying about ordering them correctly with respect to
 * existing, in-code handlers.
 * <p/>
 * Behavior is only defined for properly-nested handlers. If any "try" blocks
 * overlap (something that isn't possible in Java code) then this may not do
 * what you want. In fact, this adapter just sorts by the length of the "try"
 * block, taking advantage of the fact that a given try block must be larger
 * than any block it contains).
 *
 * @author Adrian Sampson
 */
public class TryCatchBlockSorter extends MethodNode {

	public TryCatchBlockSorter(final MethodVisitor mv, final int access,
	                           final String name, final String desc, final String signature,
	                           final String[] exceptions) {
		this(Opcodes.ASM4, mv, access, name, desc, signature, exceptions);
	}

	protected TryCatchBlockSorter(final int api, final MethodVisitor mv,
	                              final int access, final String name, final String desc,
	                              final String signature, final String[] exceptions) {
		super(api, access, name, desc, signature, exceptions);
		this.mv = mv;
	}

	@Override
	public void visitEnd() {
		// Compares TryCatchBlockNodes by the length of their "try" block.
		Comparator<TryCatchBlockNode> comp = new Comparator<TryCatchBlockNode>() {

			public int compare(TryCatchBlockNode t1, TryCatchBlockNode t2) {
				int len1 = blockLength(t1);
				int len2 = blockLength(t2);
				return len1 - len2;
			}

			private int blockLength(TryCatchBlockNode block) {
				int startidx = instructions.indexOf(block.start);
				int endidx = instructions.indexOf(block.end);
				return endidx - startidx;
			}
		};
		Collections.sort(tryCatchBlocks, comp);
		if (mv != null) {
			accept(mv);
		}
	}
}
